African-Americans who smoke appear to be at greater risk for peripheral artery disease, or PAD, new research has found. Additionally, the findings suggest that smoking intensity – how many cigarettes a day and for how many years – also affects the likelihood of getting the disease.

PAD affects 8 to 12 million people in the United States and 202 million worldwide, especially those age 50 and older. It develops when arteries in the legs become clogged with plaque, fatty deposits that limit blood flow to the legs. Clogged arteries in the legs can cause symptoms such as claudication, pain due to too little blood flow, and increased risk for heart attack and stroke.

The impact of cigarette smoking on PAD has been understudied in African-Americans, even though PAD is nearly three times more prevalent in African-Americans than in whites. The current study looked at the relationship between smoking and PAD in participants in the Jackson Heart Study, the largest single site cohort study investigating cardiovascular disease in African-Americans.

“These findings demonstrate that smoking is associated with PAD in a dose-dependent manner,” said lead researcher Donald Clark, III, M.D., an assistant professor of medicine at the University of Mississippi Medical Center, Jackson. “This is particularly important in the African-American community and supports the evaluation of smoking-cessation efforts to reduce the impact of PAD in this population.”

Even though PAD is more prevalent in African-Americans than in whites, prior studies about the disease did not include significant numbers of African-Americans. This limited the researchers’ ability to single out the specific effects of smoking in this population from other risk factors, such as hypertension, diabetes mellitus, and obesity.